Where in the first order, you se bothe in the whole nombers, and also in the numerators of the fraction, the naturalle order of nombers. And in the denominators, the naturalle progression of odde nombers.
But in the seconde order, you see that the whole nombers go in their naturalle order ,and the numerators and denominators, kepe an Arithmeticalle progression, by equalle distaunce of. 4. saue that in the numerators, all the nombers bee odde: and in the denominators, thei be all euen.
Now by this generalle rule, if you finde any twoo partes of any nomber, in one of these former proportions, you maie bee sure that it is a dimetralle nomber. But for the more apte conference of the partes, you shall doe beste to reduce them to their least nombers: as you haue learned in the firste parte of Arithmetike.
So in your last nomber, whiche was 43200. you shall finde his. 180. parte, to bee. 240. whiche beyng reduced to their smallest nombers, will bee. 3⁄4: wherfore I am assured, that it is a diametralle nomber.
Yet one thyng more shall you marke.
If any nomber ende in Ciphers, abate euen Ciphers, as often as you can (I meane. 2. 4. or. 6. &c, and if the reste be a diametralle nomber, so was the first. And therfore in this laste example. 432. is a diametralle nōber, as well as. 43200.
Also if any nomber beeyng diuided by any square nomber, doe make a diametralle nomber in the quotiente, then was the firste nomber a diametralle nomber also.
And this, for this tyme, shall suffice for diametralle nombers.
Of like
flattes.
Now will I speake somewhere briefly of like flattes: and then procede to other figuralle nombers.
Scholar. I remember you defined them before, to bee soche flatte nombers, as had one forme of proportion betwene their sides.
